As World War II came to a close, Soviet troops who had been occupied with fighting the Nazis in Europe became available for other purposes. Wishing to control as much territory in East Asia as possible after the collapse of Japan, Stalin sent his troops into Korea from the north. By agreement, the Soviet Union received the surrender of Japanese forces north of the 38th parallel. South of that line, the Japanese surrendered to the Americans. It was agreed that Korea would become a united, democratic country based on free elections, but dates were not specified. Instead, it soon became clear that the Iron Curtain had become established across the Korean Peninsula at the 38th Parallel. Tensions increased after the fall of Chiang Kai-Shek's Nationalist Chinese government and the rise to power of Mao Zedong. The United States made clear to the communists that their commitment to the security of Japan and Chiang's regime on Formosa was absolute. Unfortunately, in an address to the National Press Club on January 12, 1950, US Secretary of State Dean Acheson described the boundaries of U.S. interests in a manner that made support for Korea appear ambiguous. Whether or not this was the deciding factor, North Korea considered the time right to assert control over all of Korea. On June 25, 1950, North Korean forces moved without warning across the 38th parallel. Meeting little effective resistance, they overran Seoul in early July. North Korea's actions represented exactly the kind of aggression that should have led the United Nations to a collective response. However, as a resolution by the UN Security Council could be vetoed by any of the five permanent members, including the Soviet Union, it seemed that UN action would be blocked. And so it certainly would have been had the Soviets voted, but at the time, they were boycotting the Security Council debate over an unrelated matter, the admission of Mongolia to the UN. Realizing the opportunity that this presented, the United States and others made insincere efforts to persuade the Soviet Ambassador to attend, but he refused. Without his presence to exercise a veto, the rest of the council adopted, with only Yugoslavia abstaining, a strong resolution opposing the North Korean actions and authorizing a military response. Eventually 22 nations contributed troops, with the largest contingent of troops and commanding officers coming from the United States. The United States was stunned by the scale of North Korea's attack. The North Koreans benefited from modern Soviet weapons and made quick work of the South Koreans who opposed them. Although the US maintained large numbers of troops in Japan, the occupation had not required the same level of preparedness as had active warfare. General Douglas MacArthur sent Task Force Smith, a minimal contingent of only 540 men who engaged North Korean forces on July 5 and were quickly routed. American troops fell back amidst a chaotic flood of refugees, eventually holding a line around the city of Pusan at the southern tip of the peninsula, which became known as the Pusan Perimeter. As the Pusan Perimeter held, General Macarthur spotted a weakness in the North Korean positions. With supply and communication lines stretched thin, the North Koreans were vulnerable in the middle. On September 15, 1950, General MacArthur launched a dramatic counterattack. American and other UN troops came ashore at Inchon, the seaport of the city of Seoul, and quickly broke through the North Korean lines. Suddenly, their advanced positions became threatened from two sides, forcing the North Koreans to retreat. The UN forces were soon able to dislodge the North Koreans from all of South Korea. MacArthur was not content to return to the military status quo ante. With the North Koreans in retreat, he continued to press northward. There seemed to be no military reason to stop short of the Yalu River, beyond which lay China. Warnings began to be heard, however, which MacArthur ignored. On October 19, 1950, UN forces found themselves confronted with masses of Chinese "volunteers" all along the front lines. Willing to suffer heavy casualties, the Chinese began to push their adversaries back. Once again, American troops and their allies retreated, under conditions made worse by bitter winter weather. On January 4, 1951, communist forces recaptured Seoul. Operation Ripper pushed them back from Seoul, and a stalemate then developed with little movement of the front in either direction. President Harry S Truman now found himself in a delicate diplomatic situation. The United States had atomic weapons which neither the Chinese nor the North Koreans possessed, but using them would almost certainly bring the Soviet Union directly into the war. Even bombing attacks inside China ran grave risks. Victory might be possible, but would probably propel the world into another general war. General MacArthur did not share Truman's concern. In his view, a war should be prosecuted to the greatest extent militarily possible without regard to diplomatic risks. During the early months of 1951, his disagreements with Truman became more public. Truman felt that his constitutional role as commander in chief was being challenged. On April 11, 1951, he replaced MacArthur with General Mathew Ridgway. Ironically, a man who had held the rank of captain in World War I had fired a five-star general and war hero. MacArthur returned to the United States on the crest of widespread support. On April 19, 1951, he addressed a joint session of Congress, where he defended his views and announced his retirement from public life. Truman kept a low profile for a period of time, but the furor about MacArthur eventually waned. The war continued with no end in sight and as casualties continued to mount, the American public looked for new directions. General Dwight Eisenhower entered partisan politics as the Republican candidate for president in 1952. Promising to "go to Korea" to end the war, Eisenhower defeated Adlai Stevenson in the November elections. He visited Korea on November 29, 1951. A cease-fire was declared on April 1, setting the line between the armies near the 38th parallel, where it began. The Korean War cost 54,000 American lives. Chinese and Korean military losses were around a million, with another million civilian deaths. The war was one of the few hot wars during the Cold War period and its indecisive conclusion stood in stark contrast to the complete victory that ended World War II.